Helicopter bus



v. BENPIX HELICOPTER BUS Jan. 21, 1947.

Filed March so, 1944 s Sheets-Sheiet 1 INVENTOR. I

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A; ATTORNEYS Jan. 21, 1947. v. BENDIX HELICOPTER BUS Filed March 30, 1944' 8 shets-sneet 2 IN VEN TOR. V/NC'E/VT .Bswp/x ATT PAZEYS Jan. 21, 1947. v, BENDlx, 2,414,435

HELICOPTER BUS Filed M rch so, 1944 a Sheets-Sheet s 70.

BYW M7* W Jan. 21, 1947. I V v, BENDlX 1 2,414,435

. HELICOPTER BUS Filed March so, 1944 8 Sheets-Sheet 4 vllllykll gl sv w i Y BYW-%*W 8 Sheets-Sheet 5 Jan. 21, 1947. v. BENDIX 2,414,435

HELICOPTER BUS Filed March so, 1944 a Sheets-Sheet e INVENTOR.

Vwca/rZaz-Aw/x L; A TZOBNEYS Jan. 21, 1947. v. BENDIX HELICOPTER BUS Filed March 30, 1944 s Sheets-sheet 7 @4412 40 ATTQBAIEYS Ma S 0 N Jan. 21, 1947. v, BENDlX 2,414,435

HELICOPTER BUS Filed March so, 1944 a sheets-sheet a Ab ATTORNEYS I Patented Jan. 21, 1947 HELICOPTER BUS Vincent Bendix, Flemington, N. J assignor to Bendix Helicopter, Inc., New York, N. Y., a corporation of Delaware I Application March 30, 1944, Serial No. 528,731

16 Claims. 1

This invention relates to improvements in helicopters It relates particularly to improved forms of helicopters having a plurality of sets of coaxial, counter-rotating rotors and to the control mechanism therefor, whereby movement in any direction and pitching and rolling about the transverse and longitudinal axes and turning about the vertical axis of the helicopter may be attained and controlled.

In my copending application Serial No. 511,408, filed November 23, 1943, a form of helicopter is disclosed having a coaxial, counter-rotating rotor unit and the various controls therefor. This form of helicopter is characterized by rotor wings having mechanisms, such as flaps or blades, mounted thereon whereby the sectional shape of the wings can be changed cyclically to propel the helicopter in a horizontal plane, to vary the lift of the wings, to compensate for variation in air speed in the rotor wings, and to correct for or to cause pitching and/or rolling and turning of the helicopter.

The present invention constitutes an improvement over the disclosure of the above-mentioned application, and has as an object the provision of a helicopter which is capable of lifting and transporting greater loads than is possible with a single or double rotor helicopter.

Another object of the invention is to provide helicopters having a plurality of counter-rotating, coaxial rotor units connected by a centralized system for controlling the movements of the helicopter.

Another object of the invention is to provide helicopters with a plurality of interconnected counterrotating, coaxial rotor units driven by a plurality of engines each of which can drive all of the rotors, whereby failure of one or more of the engines will not disable any of the rotors.

Other objects and advantages of the present invention will become apparent from the following description of typical forms of helicopters embodying the invention.

In accordance with the present invention, I have provided a helicopter having a high load carrying capacity and including a plurality of rotor units generally of the type disclosed in my application Serial No. 511,408. The helicopter may be used as a multi-passenger bus or a cargo carrier and is provided with a body of appropriate type. In order to control the action of the rotor units, I provide a centralized control system of novel type that interconnects the units so that the various adjustments to which each of the units is susceptible may be made to change the direction of flight or propel the helicopter in any direction,

maintain it level in flight and control the pitching and rolling of the helicopter.

More particularly, the control system for my multi-rotor unit helicopter includes centralized means for varying the pitch of the rotors to control ascent and descent of the helicopter and to cause a change in direction of the helicopter when desired. Moreover, the centralized control system includes means which is capable of varying, at

will, the lift of the wings of the rotors in order to overcome rolling or pitching of the helicopter and thereby maintain it level in flight and offset any tendency toward instability of the helicopter. In addition, the control system includes control mechanism for varying the sectional shape of the wings, for example, by varying the extent of projection of the propelling blades on the wings in order to vary the speed and the direction of flight as well as the lift of the wings.

The control system described generally above permits the use of two or more of the rotor units so that the lifting effect obtainable therewith may be multiplied without excessively increasing the size of the individual rotors to such an extent that they would be weakened or would be unwieldly or ungainly.

For a better understanding of the present invention, reference may be had to the accompanying drawings, in which:

Figure 1 is a view in side elevation of a typical form of helicopter embodying the present invention;

Figure 2 is a plan view of the helicopter of Figure 1;

Figure 3 is a front view of the helicopter;

Figures 4a and 4b are views in vertical section and partly broken away of a rotor unit of the type used in the helicopter;

Figure 5 is a view, partly in section, of a portion of a rotor wing;

Figure 6 is a view in section taken on line 6-6 of Figure 5;

Figure 7 is a view of the rotor units illustrating connections therebetween for coupling the units for synchronous operation;

Figure 8 is a view in cross-section of a form of differential used for coupling the rotor units;

Figure 9 is a view, partly in section, of another coupling element for the rotor units Figure 10 is a view in side elevation and partly in section and broken away illustrating details of the universal joints utilized in coupling the rotor units; I

Figure 11 is a diagrammatic showing of a typical form of control system for a two rotor unit helicopter; and

Figures 12-17, inclusive, are views of details of the elements of the control mechanism.

The form of helicopter chosen to illustrate the present invention and disclosed in Figures 1, 2 and 3, includes a bus-like body Ii] of generally aero-dynamic form and being relatively long and narrow in order to reduce the wind resistance thereof. The body I!) may be provided with a plurality of observation windows I I along the sides thereof and provided with two rows of seats, not shown, in the conventional way and a front compartment I2 for the operator or pilot. The lower section IIIa of the body may be provided with a plurality of doors I 3 closing baggage compartments or access openings therein.

In front and behind these compartments I3 are located other compartments for the motors and indicated generally as to location by the ventilating louvres Iflb and I at the front and rear of the body It. The body It may be provided, also, with pneumatic tire wheels I4. The front wheels I4 may be mounted in the manner of the conventional front wheels of buses or other vehicles in order to permit the helicopter to be steered along the ground. If desired, floats may be substituted for the wheels I4, I4. 'Moreover, the body may be modified to suit it for freight instead of passengers, as desired.

As shown particularly in Figures 1 and 2, the bus is provided with a pair of coaxial, counterrotating rotors I5 and I6 adjacent its forward end and with a similar pair of coaxial, counterrotating rotors I5 and I6 adjacent the rear end of the vehicle. The front rotor unit I? includes the rotors I5 and I6, a transmission and one or more motors for driving the rotors, Usually, two motors is the most desirable number. The rear rotor unit I'I" includes the rotors I5 and IS, a transmission and motors for driving the rotors like those of the rotor unit ll.

The individual rotor units II and ll, of which the rotor unit Ii, only, will be described herein, are similar to the rotor unit disclosed in my copending application Serial No. 511,408. Referring now to Figures 4a and lb, each rotor unit preferably is provided with a pair of engines, not shown, which may be'of the radial air-cooled type, if desired. These engines are provided respectively with the driveshafts I8 and I9 which are in axial alignment and project into the opposite sides of a gear housing 28. The gear housing 2a is provided with a generally cylindrical extension 2! in which is mounted a ring gear 23 cooperating with a series of planet gears 24, and asun gear 25', that is fixedly mounted on the driveshaft Is. The planet gear system described above effects a reduction in speed between the driveshaft I8, for example, and the sleeve 25 upon which the planet gears 24 are rotatably supported. The sleeve 26 cooperates with a second sleeve 21 supported by means of roller bearings 28 on a sleeve 25a fixed to the sun gear 25 and concentric with the shaft I3 to form an overrunning clutch in which the rollers 29 form the coupling elements between the sleeves.

The sleeve 21 1s suitably supported in an anti friction bearing 3t carried by a partition 3i in the housing 2% The sleeve 21 is provided with a bevel gear 21a which meshes with a pair of bevel gears 32 and "33 journaled in the end plates 34 and 35 of the housing 20, for rotation in opposite directions by the bevel gear 27a.

The driveshaft I9 is coupled in a similar manner to the bevel gears 32 and 33' and inasmuch as it is driven in the opposite direction from the shaft I8, it tends to rotate the gears 32 and 33 in the same direction. The elements connecting the shaft E9 to the gears 32 and 33 corresponding to the elements 2!, 23, 24, 25, 25a, 26, 21, 21a, 28, 29, 36 and 3I are identified as the elements 2|, 2%, 24', 25, 25a, 26, 21', 21a, 28, 29', 30' and 3 I Inasmuch as the bevel gears 21a and 21a on the shafts I8 and I9 are capable of. overrunning the shafts I8 and I9, stoppage of either of the shafts I3 or I9 will not stop the rotation of the gears 32 and, 33. On the contrary, these gears will overrun either or both of the shafts I8 and 59 so that the rotors I5 and I6 associated therewith can continue to rotate even with both of the motors stopped.

The rotor I6 is carried by a tubular shaft 36 that is fixedly connected to the gear 32 and rotatable therewith. This shaft is journaled in the upper end of a conical housing 31 that is supported on the top of the gear housing 20 so as to stiffen and prevent whipping or bending of the shaft 35.

The rotor I5 is similarly mounted on a tubular shaft 38 that is fixed to the gear 33 and extends upwardly within and concentric with the shaft 36. The shaft 38 projects beyond the end of the shaft 36 and is journaled in a generally conical housing 39 fixed to the upper surface of the rotor It.

Referring now to Figures 413, 5 and 6, each of the rotors I5, I5, I5 and I6 is generally the same with the exception that the wings of the rotors I5, I5 face in the opposite direction from the wings of the rotors I6 and I3. Inasmuch as these rotors are substantially the same, only one of them will be described herein. Each of the rotors, for example, rotor I5, includes a hub portion 40 that is fixed to the end of its cor-' responding driveshaft, for example, the driveshaft 38. The hubs 46 are of generally tubular formation and are provided with sockets 43a for receiving one end of a tubular spar 4I that extends substantially throughout the length of the rotor wings 42. As shown particularly in Figure 4b,

the end portion 4Ia of the spar M is provided with a shoulder 4Ib that engages a thrust bearing 43 that is retained in the end of the hub 40 by. means of a threaded sleeve 44. The thrust bearing 4Ib prevents the spar M from being thrown outwardly by centrifugal force. The inner end of the section 4Ia. of the spar is provided with a pair of diametrically spaced lugs He that engage in oppositely inclined slots 45 in a sleeve 46 that is mounted concentrically within the shaft 38 and pinned thereto against rotation, but capable of axial sliding movement. Axial movement of the sleeve 46 will cause a rocking or rotation of the spar 4| about its axis to vary the pitch of the wing 42, as will be described.

Each of the wings 42 is of aero-dynamic crosssection, as shown in Figure 6 of the drawings. The spar 4| which extends axially of the wing stiffens or rigidifies the wing longitudinally and thereby prevents distortion of the wing. The spar 4| also acts as a support for the actuating mechanisnr for a flap-like propeller blade 4! which is movable from a, position within the section of the wing 42 to positions projecting from the wing as illustrated in dotted lines. The propeller blades 41 may include a plurality of hollow rib-like members 41a, the lower surfaces of which are covered with a metallic skin 41b so that when the blades are disposed Within the section of the wing, a substantially continuous outline is provided. Each of the ribs is provided with a tubular portion 410 having spiral threads or teeth therein for cooperation with complemental spiral teeth or threads 48 on a shaft 49 that extends longitudinally of the wing 42 substantially parallel to the spar 4|. The tubular portions 410 of the blade ribs are suitably journaled in tubular journal members 50 that are supported by pairs of webs 5! that projectrearwardly from the spar 41. Thus, the propeller blade is capable of pivotal movement about the axis of the shaft 49, and the shaft 49 is supported by the tubular portions 410 and the journal members 59. Because of the threaded connection between the shaft 49 and the ribs 41a, axial movement of the shaft 49 inwardly will project the propeller blades 41 and axial movement outwardly will retract the propeller blades.

In order to prevent rotation of the shaft 49, the latter is provided with arms 52 projecting therefrom which carry adjacent their ends rollers 53 that engage the tracks 54 carried Iby the Webs 5! on the spar 4|.

By providing the proper thread on the shaft 49, the movements of the shaft and the propeller blades may be coordinated so that centrifugal force acting on the shaft 49 will tend t retract the propeller blades 41 and inward movement of the shaft 49 will tend to project the propeller blade.

From the preceding description of the support and the structure of the rotors and the rotor wings, it will be apparent that the rotors can be varied in pitch and the propeller blades can be projected and retracted relatively to the wings.

The mechanism for varying the pitch of the rotor wings is disclosed in Figures 4a and 4b. As shown particularly in Figure 4b, the pitch-varying sleeve 49 is supported by a tubular shaft or sleeve 55 mounted concentrically within the shaft 38 and extending down into the housing 29. The lower end of the sleeve 55 is provided with a collar 56 fixed thereto which is received rotatably in a ring-like channel member 51 forming a portion of a lever that is pivotally supported in the lower end of the housing 28. The opposite end 51a of the member 51 is provided with a pivotally movable internally threaded sleeve 58 that receives the lower threaded end of a rod 59 extending vertically in the housing 29 and having an upper end projecting therefrom.

The lower rotor 16 has a similar pitch-varying sleeve and shaft 60 that extends downwardly into the housing 29 and is similarly provided with a collar or flange 6| rotatably received in the lever 62. The free end 620. of the lever 62 is provided with a pivotally mounted internally threaded sleeve 63 that engages an oppositely threaded portion of the shaft 59 whereby upon rotation of the shaft 59, the sleeve shafts 55 and 6B are moved in opposite directions and. upon axial movement of the shaft 59, the sleeve shafts 55 and 69 move in the same direction simultaneously. Thus, upon axial movement of the shaft 53, the pitch of the blades of the rotors l5 and IB can be varied simultaneously in the same sense. Upon rotation of the shaft 59, the pitches of the rotors are varied in opposite senses. In this way, the lift of the rotors can be equalized, if desired, or th torque reaction of the rotors varied so as to tend to cause the housing 20 and the motors affixed thereto to rotate in the opposite direction to the direction of rotation of the rotor having the greater pitch angle. Such variation in the torque reaction can be utilized to steer or turn the helicopter.

The projection and retraction of the propeller blades 41 is varied in order to propel the helicopter in a desired direction, to compensatefor variation in lift due to variation in air speed of the rotor wings and to cause rolling of the helicopter. Thus, when the propeller blades on the wings of the rotors l5 and 15 that are traveling rearwardly are projected an equal amount and for an equal period of time, there is created a rowing action which tends to propel the helicopter forwardly. Atthe same time, the sectional shape of the wing is altered and increased lift is imparted to that wing having the projected pro peller blade. Such increased lift tends to compensate for the decreased lift that is caused by motion of the entire helicopter in a direction opposite to the direction of motion of the wing or to compensate for the decreased air speed of the rearwardly moving wing as compared with the increased air speed of the forwardly moving wing at the opposite side or end of the rotor. Such compensation for air speed tends to increase the stabilityof the rotor system and to reduce the tendency of the wings to vibrate in a vertical plane as they rotate.

The mechanism for actuating and controlling the propeller blades will now be described.

Each of the propeller blades is provided with mechanism for causing the shaft 49 to reciprocate axially of the blade. As illustrated, the inner end of the shaft 49 is connected to the one end of a lever 65 that is pivotally mounted on the rotor hub and has its other end pivotally connected to a carrier 6% for a roller 61. A second parallel lever 58 is also connected to the hub 49 and the roller carrier 65 to maintain the roller substantially perpendicular to the axis of the driveshafts 38 and 35. The roller $1 on the rotor l5 cooper ates with a cam sleeve 69 that is carried by a tubular shaft 18 concentric with the driveshaft 38, disposed within the shaft- 55 and extending downwardly into the bottom of the casing 20. The shaft 1!] is provided with a worm gear H that meshes with a worm 12 rotatably mounted in the bottom section 29a of the casing 20 so that upon rotation of the Worm 12, the shaft 10 can also be rotated, as well as the cam sleeve 69 carried at the upper end of the shaft. The cam sleeve 69 is also supported for axial movement and rotation upon a collar 13 carried by the hub of the rotor Hi.

In addition to rotary movement of 'the shaft 18, it is capable of axial movement relatively to the worm gear 1! mounted thereon by means of a shiftable collar 14 that engages rotatably a flange Illa on the bottom of the shaft 13. In order to permit such axial movement of the shaft 14 the worm gear 1! may be splined to the shaft 50.

The cam sleeve 69 may be provided with two substantially oppositely directed cams 69a and bylindrical portion of the cam 69 and due to air pressure on the propeller blades 41 and centrifugal forces on the shaft 49, the propeller blades 7 will not be projected. If the cam sleeve 69 is moved upwardly from the position shown, the rollers 61 when passing over the cam lobe 69a will be displaced outwardly, drawing the shafts 49 inwardly in succession and thereby projecting and retracting the propeller blades ll on the opposite wings of the rotor l successively and in the same sectors of the circle of rotation of the rotors. As the cam sleeve 69 is moved upwardly to a still greater extent, the propeller blades 41 will be projected from the wing a correspondingly greater distance and over a correspondingly wider arc, thereby exerting a greater thrust on the air.

If the sleeve is moved downwardly so that the rollers 51 engage the cam 6%, the same elfect will be obtained, except the blades will be projected in an are spaced diametrically from the arc in which the blades are projected by the cam 69a. This action may be utilized, for example, to cause the helicopter to move backwardly rather than forwardly.

By rotating the cam sleeve 69, the arc of the circle of rotation may be displaced correspondingly so that the angle of thrust of the blade may be changed with respect to the longitudinal axis of the helicopter and the lift exerted by such propeller blades exerted in a different sector of the circle of revolution. This rotary adjustment may be used for trimming or equalizing the propulsion effect of the rotors of the unit. a

The cam mechanism for the rotor it is similar in that it includes a cam sleeve l5 mounted beneath the rotor It and carried by the tubular shaft it which projects downwardly into the conical casing 31 and is rotatably mounted Within it with capacity for axial movement. As shown particularly in Figure 4a, the shaft 15 is splined to a worm gear I? that cooperates with a worm 18 mounted in the housing 31. The lower end of the shaft 76 is provided with a flange Ma which may be moved up and down to vary the axial displacement of the cam. A ring 19 is rotatably mounted on the flange 16a, as shown in Figures 4a and 11.

As shown in Figure 4b, the cam sleeve 15 is rotated with respect to the cam sleeve 69 so that the propeller blades on the rotor 16 will be projected through an are on the opposite side of the longitudinal axis of the helicopter from the are through which the propeller blades on the rotor H; are projected in order to provide a rowing action for propelling the helicopter.

The above-described rotor unit, therefore, is provided with means for simultaneously or variably changing the pitch of the rotors of the unit, a mechanism for projecting and retracting the propeller blades on the rotors and an adjusting mechanism for varying the extent of projection of the propeller blades.

As disclosed in Figures 13 and '7, two of the rotor units I1 and W are utilized for lifting and propulsion of the vehicle.

The two units may be synchronized or governed to operate at the same speed, but preferably they are interconnected as shown in Figure 7 by means of suitable connectingshafts, universal joints and a reversing gear in order to permit the corresponding rotors to rotate in the same direction. Thus, the rotor unit I! is provided with a reversing gear mechanism 80 which drives a shaft Bl that is connected by means of a universal joint 82 to'another substantially coaxial shaft 83. This latter shaft is connected by means of auniversal joint 84 to another shaft 8 that is connected by means of a coupling to the rotor unit ll.

The reversing gear 80 is illustrated more particularly in Figure 8 of the drawings and includes a hollow generally cylindrical casing 81 provided with a bearing 88 at its left-hand end for receiving a double bevel gear 89. One gear element 89a meshes with the bevel gears 32 and 33 within the housing 20 and, extends thereinto at substantially a right angle to the axis of the shafts l8 and 19. The casing Bl may be secured to the housing 20 by means of bolts or other fastening means extending through the flange 81a on the casing 81.

The bevel gear 8% meshes with a pair of differential gears 98 and 9! that are mounted for rotation about an axis at a right angle to the axis of the gear member 89. The gears 90 and BI may be provided with bushings 92 and 93, respectively, through which pass a bolt 94 that extends transversely of the casin 8'5. A spacer membe 95 is also supported on the bolt 94 in order to maintain the gears 90 and SI in proper spaced relationship. These gears in turn mesh with a bevel gear 95 which is splined to a shaft 8! that is supported in suitable anti-friction bearings 98 in a reduced portion 81b of the casing 31. The bearing 98 may be retained in engagement with an internal shoulder 810 by means of an annular retaining plate 89.

The bevel gear 96 is retained on the shaft by means of a nut 1% threaded on the end of the shaft 8| and the shaft is maintained otherwise against axial movement by means of a flange Bla thereon. V

The coupling 8% between the shaft 85 and the unit [1' is shown in Figure 9. This unit includes a generally frusto-conioal housing IEH having an anti-friction bearing I02 supported in its larger end for receiving rotatably a bevel gear Hi3 that meshes with the gears of the unit l1 corresponding to the gears 32 and 33 of the unit H. The bevel gear IE3 is splined to the end of the shaft 85 and is provided with a sleeve portion 13a concentric with the shaft 85. The gear N13 is retained on the shaft 85 by means of a nut [04' threaded on the end of the shaft and a collar 85a fixed to the shaft and bearing against the inner race of an anti-friction bearing I05. The opposite side of the race is engaged also by the sleeve l03a. The above-described arrangement prevents endwise shifting of the gear I 03 and the shaft I05.

The universals 82 and 84, which are substantially identical, are illustrated more particularly inFigure 10. As shown in section in Figure 10, each of the universal units includes a casing W3 having a reduced portion llifia that is splined to the shaft 8i or 85. The housing I96 is retained on the shaft 8!, for example, by means of the nut ifl'i threaded onto the end of the shaft The casing W6 i provided with inner peripheral teeth Hi3 which engage arcuate teeth IGSa on the cooperating universal unit I03. The arouate teeth 4 99a permit relative rocking of the casing Hit and the member 39 as well as relative axial movement, if necessary. The inner universal unit W9 is provided with a sleeve portion llliib that is splined to the shaft $3 and is also received in an anti-friction bearing I It that may be supported by a journal member I ll fixed to a portion of the body of the helicopter. The shaft 83 and the member I99 are retained in fixed relationship bymeans of a nut H2 bearing against the end surface of the member I09 and threaded on the end of the shaft 83.

The above-described connections between the rotor units I! and I1 permit ready alignment of the shafts 8|, 83 and 85 or compensate for slight misalignment. The differential unit 80 operates to cause the motors to drive both units I'Iand IT in the same direction. In this way, the device can be operated on fewer than the total number of engines provided in the device. Both setsof rotor units I'I, I1 can be driven by the motors of one of these units or one motor of each unit.

The control system for the device is disclosed diagrammatically in Figure 11 of the drawings and details of the various elements of the control are shown more particularly in Figures 12-17 of the drawings. As shown in Figure 11, the two rotor units I! and II are disposed in approximate alignment and preferably rearwardly of the pilots seat II5. A plurality of manually operated levers and foot pedals are provided for giving the necessary control over the operation of the rotor units of the device. In order to vary the pitch of the rotors of the two units I1 and II to vary the lifting effect as in taking ed and landing, a control lever I I6 is pivotally supported adjacent the seat II5. This lever II6 hasits rear end portion connected by means of a link II! to a pivotally supported bell crank lever H8. The other arm of the bell crank lever is connected by a link H9 to the lower end of a lever I20 which may be pivotally mounted on the rotor unit I1 or on an adjacent portion of the body I of the helicopter. The upper bifurcated end of the lever I20 is connected to a control member I2I, shown more particularly in Figure 12 of the drawings. As shown in Figure 12, the member I2I consists of a tubular portion I22 having a collar I23 rotatably mounted thereon provided with pins I23a that engage the opposite arms of the lever I20. The collar I23 may be provided with one or more set screws I23b that project into an annular groove I22a in the member I22,

The member I22 is also provided with oppositely extending lever arms I22b and I220 for a purpose to be described herein. The opposite end portions of the member I22 are provided with oppositely directed internal threads for engaging the threaded portions of the shafts I24 and I25 so that rotation of the member I22 causes the shafts I24 and I25 to move in opposite di rections.

The shaft I24 is coupled to the upper end of a pivotally supported bell crank lever I26, preferably mounted on the rotor unit I1 and having its opposite lever arm connected to the upper end of the shaft 50 by means of a sliding pivot connection I21.

As described above, upward and downward movement of the shaft 59 will cause a, change in pitch of the rotors I and I6. in the same sense and to the same extent.

The shaft I25 is pivotally connected to the upper end of the lever I28 which is pivotally supported at its mid-portion and has its opposite ends connected by means of the cables I29 and I30 to the corresponding ends of a three-arm lever I3I that is pivotally mounted adjacent the rotor unit II. The third arm I3 Ia of the lever is connected by means of a sliding pivot connection I32 to the upper end of the shaft 59' of th unit II. The shaft 59' corresponds to the shaft 59 Ofthe unit II.

Connections described above are such that when the lever H6 is in the position shown, the rotors I5, I6, I5 and I6 ar inneutral pitch position. When the lever I I6 is moved in a clockwise direction or upwardly, the pitch of each of these rotors is increased, as, for example, when y it is desired to take off.

In order to steer the helicopter, the helicopter is provided with a pair of pedals I33 and I34, shown in Figures 11 and 13. As shown in Figure 13, the pedals may consist of U-shaped members having their ends journaled on a shaft I35 that is fixed in a U-shaped bracket I36. The pedal I33 is provided with a rearwardly projecting lever arm I31 that is pivotally connected by means of a link I38 to one arm I39a ofa threearm lever 39. The pedal I34 is also provided with a rearwardly extending lever arm I40 that is connected by means of a link IM to the opposite arm I39b of the lever I 30. The lever I30 is suitably supported for pivotal movement in a bracket I42 fixed to the framework of the helicopter body I0. The lowermost arm I390 of the lever I39 is connected by means of a link or rod I43 to a lever I44, best shown in Figure 14, The lever I44 is slidably, but non-rotatably, supported on the shaft 50 by means of a spline, or key and slot connection I45. The outer end of the lever I44 may be connected pivotally to a reduced nor tion I43a of the shaft I43. The opposite end of the shaft I43 is connected to a lever I46, best shown in Figure 15 of the drawings. The lever M6, like the lever I44, is slidably, but non-rotatably, connected to the shaft 59 by means of a spline, or key and slot connection I41,

The above-described construction affords a means of varying relatively the pitches of the rotors I5, I5 and the pitch of the rotors I61 and I6. Thus, if the pedal I33 is depressed, the lever I39 is rocked in a clockwise direction, moving' the shaft I 43 to the left and rotating the shafts 59 and 58' in a clockwise direction, as viewed from above, thereby increasing the pitch of the rotors I5 and I5 and decreasing the pitch of the rotors I6 and I6. The unequal torque reaction created by varying the pitch and the torque-of the rotors tends to turn the helicopter to the left in the direction of the depressed pedal I33. Similarly, depression of the right-hand pedal I34 increases the pitch of the rotors I6 and I6 and decreases the pitch of the rotors I5 and I 5' causing the helicopter to turn to the right.

In order to control the action of the propeller blades 41 in propelling the helicopter, a second lever I50 is provided adjacent the lever H5. The lever I50 has a cable I5! connected thereto above its pivot point which extends over the pulleys I52 and I53 to a coupling yoke I54. Similarly, the lower end of the lever I53 below its pivot is connected by means of a cable I55 passing over the pulleys I56 and I5! to a coupling yoke I58.

The coupling yokes I54 and I58 are connected to each other by means of a cable I 59 that passes over a roller I65 and is connected to a control unit I6! and through the control unit Hill by means of a cable I 62 that passes over a pulley I63 to the coupling member I58. Thus, upon movement of the lever I50, the cables described above cause the coupling yokes I54 and I58 to move in opposite directions and the member IBI is moved up or down. The member IBI is best shown in Figures 11 and 16 of the drawings. This member includes a tubular sleeve I64 having the pairs of lugs H540; and I64b thereon to which the cables I59 and I62 are connected, respectively. The opposite ends of the member I64 are provided with oppositely directed internal threads I640 and IBM which receive the threaded shafts I65 and I66. The coupling member I64 is also provided with oppositely directed lever arms I64e and IBM by means of which the coupling sleeve I64 can be rotated. The upper shaft I65 is pivotally connected to a pivotally mounted lever I61 which has its opposite end coupled to the collar 19 by means of which the shaft 16 is moved upwardly and downwardly. As described above and shown in Figure 4b, the shaft 16 carries the cam sleeve 15.

The shaft I66 is connected to one end of a pivotally supported lever I68, the opposite end of which is connected by a link I69 to another lever I19. The lever I19 is mounted on a shaft I 86 which carries a fork ISI that engages the collar I4 at the lower end of the sleeve shaft 16, as shown in Figures 4a and 11. The upper end of the shaft carries the cam sleeve 69, as described above.

The coupling yoke I54 is also connected by means of a cable I82 to another member I64 similar to that described above and this member is in turn connected by means of a cable I83 to the coupling yoke I58. The member I64 is connected to the corresponding cam sleeve shafts of the unit I1 in the same manner as the member I64 is connected to the shafts 16 and 16. Thus, upon movement of the lever I59, the coupling members I64 and I 64 associated with the units I1 and I1 move up and down together. Such movement of the members I64 and I64 will cause a corresponding shift of the cam sleeves 69 and 15 of unit I1 and the corresponding cam sleeves of the unit I1, in such a manner that forward movement of the control lever I56 will cause the propeller blades 41 to be projected from the rotors I5, I5, I6 and I6 during their rearward movement relatively to the axis of the helicopter body I6, thereby propelling the helicopter forwardly. When the lever I50 is drawn backwardly, the cams 69 and 15 are shifted so that the follower rollers 61 will engage the rearward motion cams 69b and 15b and will cause propeller blades 41 to be projected in such a manner as to cause the helicopter to move backwardly.

The above-described controls regulate the forward or rearward movement of the helicopter, the turning movement of the helicopter and the rising and settling movements thereof. Other controls are required to correct for unwanted motions of the helicopter, for example, pitching movement or rolling movement or to cause pitching and/or rolling to maintain the helicopter in level flight. The mechanism for controlling motion about the longitudinal and transverse axes of the helicopter will now be described.

Adjacent to the pilots seat H5 and convenient for manipulation by the pilot is a third pitch ing and rolling control lever I85. The lever I85 has its lower end pivotally connected to a tubular member I96 which is rotatably mounted in suitable bearing" members I81 supported on the floor of the pilots compartment. The forward end of the tube carries a pulley I88 having its lower edge coinciding substantially with the axis of the tube I66. In addition, as shown in Figure 1'1, the tube is provided with laterally projecting lever arms I86a and IBM).

The lever I85 is connected to a cable I89 which passes over the pulley I88 and then. extends through the tubular member I .86, overthe pulley I96 and downwardly to the member HI, and is connected to the arm I220 thereof. The lever I is also connected by'means ofa cable I9I to the lever arm I221) of the member I2I. Thus, upon forward movement of the control lever I85, the lever I221) is lifted, while the lever arm I220 is depressed, as viewed in Figure 12, thereby rotating the tube I22 in such a direction as to move the shafts I24 and I25 toward each other[ As a result, the shaft 59 is moved downwardly, while the shaft 59 of the rotor unit I1 is raised. The opposite directions of motion of the shafts 59 and 59 cause a variation in pitch of the wings of the rotor units I1 and I1. Theforward movement of the stick will tend to cause an increase in the pitch of the wings of the rotor unit I1 and a decrease in the pitch of the wings of the rotor unit I1 and will tend to depress the forward end of the helicopter and raise the back end of the helicopter. Similarly, rearward movement of the control lever I 65 will increase the pitch of the Wings of the forward rotor unit I1 and decrease the pitch of the wings of the rear rotor unit I1 with the result that the helicopter will tend to nose up about its transverse axis.

Rolling of the helicopter about its lon itudinal axis is controlled by right and left movement of the control lever I85. As indicated above, the member I66 is rotatably mounted and, therefore, this member moves with the control lever I85 in its rocking movements to the right and left. In order to utilize such rocking movements, the lever arm I861) is connected by means of a cable I92 to the lever arm I64] of each of the members I6I and I6I'. The other arm I86a is connected by means of a cable I93, Figure 1'7, to the arm I64e of the members I64 and I64 of the rotor units I1 and I1. Thus, upon movement of the control lever I85 to the left with relation to the pilots position will exert a pull on the cable I93 and a slackening of the cable I92 so that members I6I and I6I' are both rotated in a clockwise direction. Such clockwise rotation will tend to move the shafts I65 and I66 toward each other, thereby moving the two cam sleeves 69 and 15 of each unit upwardly, as viewed in Figure 11.

Such upward movement of the cam sleeve 69, assuming that the helicopter is travelling forwardly, will increase the extent of projection of the propeller blades of the rotor I5 and will decrease the extent of projection of the propeller blades on the rotor I6. This adjustment will decrease the lift of the rotors l6 and I6 during their rearward movement in their circle of rotation and will increase the lift. of the rotors I5 and I5, thereby tending to roll the helicopter about its longitudinal axis toward the left or in the direction. of movement of the control lever I85. Similarly, movement of the control lever I85 to the right will cause the helicopterto roll to the right about its longitudinal axis. These controls are effective even when the power to the rotors is completely shut off and the rotors are windmilling.

In addition to the propulsion effect obtained by means of the propeller blades, the axes of the rotors may be placed at a small angle to the vertical so that there will be a thrust component in a direction to urge the helicopter forward, when the body IIlis horizontal; thereby'increasing the speed of the helicopter; During vertical ascent and descent, it will be necessarywithth is arrangement'to tilt the body the horizontal.-

From the above description, it will be apparent that I have provided a control system whereby the direction of flight can be controlled, the helicopter can be caused to turn right or left, as desired, and can pitch about its transverse axis as well as roll about its longitudinal axis in response to operation of the various controls. By proper coordination of these various controls, the helicopter can be caused to rise vertically, travel forwardly or rearwardly and be maintained in level flight with any of these motions.

While I have described the invention with reference to a specific embodiment of the same, it will be understood that other types of control mechanisms operating in a similar manner may be used without departing from the invention. Therefore, the form of the invention described above should be considered as illustrative and not as limiting the scope of the following claims.

I claim: I

1. In a helicopter, the combination of an elongated body, a rotor unit adjacent each end thereof, each rotor unit comprising a pair of coaxial, variable pitch rotors, and means for rotating the rotors in opposite directions, means for controlling the pitch of each of the rotors and means including control connections interconnecting the pitch control means of both units for varying the pitches of the rotor units rotatable in one direction in one sense and varying the pitches of the rotors rotatable in the opposite direction in the opposite sense, and including control connections for simultaneously varying the pitches of the rotors of one unit in one sense and the pitches of the rotors of the other unit in the opposite sense.

2. In a control system for a helicopter having a plurality of counter-rotating, coaxial rotor units, each unit being provided with at least two variable pitch rotors; the combination of means for varying the pitch of all of the rotors simultaneously in the same sense, means for varying the pitches of the rotors of the units rotatable in one direction in one sense and varying the pitches of the rotors rotatable in the opposite direction in the opposite sense, and means for simultaneously varying the pitches of the rotors of one of the units in one sense and varying the pitches of the rotors of the other rotor unit in the opposite sense, each of said means being connected with both of said rotor units.

3. In a control system for a helicopter having two rotor units, each rotor unit comprising a pair of variable pitch, coaxial rotors having at least two Wings, means for varying the pitch of each rotor, and means for rotating the rotors in opposite directions; a control lever for varying the pitches of all of the rotors of both units simultaneously and in the same sense, steering mechanism connected to said pitch varying means for varying the pitches of the clockwise rotating rotors simultaneously in one sense and varying the pitches of the counter-clockwise rotating rotors simultaneously in the opposite sense and a stabilizing lever movable in one plane for varying the pitches of the rotors of one of said units in one sense and simultaneously varying the pitches of the rotors of another unit in the opposite sense.

4. In a helicopter, the combination of an elongated body; a rotor unit mounted in each end of said body, each unit having a pair of coaxial, variable pitch rotors, means for rotating said It with respect to rotors in opposite directions and means including a shaft movable axially to vary the pitches of said rotors in the same sense, and rotatable for varying the pitches of said rotors in opposite senses; a first control member connected to the shafts of said rotor units for simultaneously moving said shafts axially; and a second control means for rotating said shafts simultaneously.

5. In a helicopter, the combination of an elongated body; a rotor unit mounted in each end of said body, each unit having a pair of coaxial, variable pitch rotors, means for rotating said rotors in opposite directions, and means including a shaft movable axially to Vary the pitches of said rotors in the same sense, and rotatable for varying the pitches of said rotors in opposite senses; a first control member connected to the shafts of said rotor units for simultaneously moving said shafts axially in the sam direction; a second control means for rotating said shafts simultaneously; and a third control means for moving said shafts axially in opposite directions.

6. In a helicopter, the combination of an elongated body having a rotor unit adjacent each end thereof, each rotor unit comprising a pair of coaxial variable pitch rotors having at least two wings, means for varying the sectional shape of said wings, and means for rotating said rotors in opposite directions; control means connected to both of said units for selectively varying the pitches of said rotors to regulate their lift and their torque reactions, and other control means connected to both of said units for actuating the sectional shape varying means in predetermined cycles.

7. In a helicopter, the combination of an elongated body of aerodynamic shape, a rotor unit adjacent each end thereof, each rotor unit comprising a pair of coaxial, variable pitch rotors,

having projectable and retractable propeller blades thereon, and means for rotating the rotors in opposite directions; means connected to both of said units for controlling the pitches of the rotors of said units to vary the lifting effect and torque of said rotors and means for cyclical- 1y projecting and retracting the propeller blades and for varying the extent of projection of said blades, whereby the body may be caused to roll about its longitudinal axis, pitch about its transverse axis and turn about its vertical axis.

8. In a helicopter, the combination of an elongated body having a rotor unit adjacent each end thereof, said rotor units each comprising a pair of coaxial, variable pitch rotors having at least two wings, means for rotating the rotors in opposite directions, and means for varying the sectional shape of said Wings to vary thelift and thrust of said wings, a control member for varying the pitch of all of said rotors simultaneously and in the same sense, control means for varying the pitch of the rotors of one of said units in one sense and varying the pitch of the rotors of the other unit in the opposite sense, control means for varying the pitches of the clockwise rotating rotors of both units in one sense and varying the pitches of the counter-clockwise rotating rotors in the opposite sense, and control means for varying the sectional shape of said wings, in a desired cycle.

9. In a control system fora helicopter, the combination of a multi-passenger body, at least two counter-rotating, coaxial rotor units, each provided with at least two variable pitch rotors, and each rotor having at least two wings, means for varying the sectional shape of the wings cyclically, control means connected to both of said units for varying the pitches of said rotors selectively in the same sense and in opposite senses, and means connected to both of "said units for controlling the sectional shape varying means.

10. In a control system for a helicopter having two rotor units, each rotor unit comprising a pair of variable pitch, coaxial rotors having at least two wings, propeller blades movably mounted on said Wings for varying the thrust of the Wings in their plane of rotation and the lift of said wings, means for projecting and retracting said blades cyclically, means for varying the pitch of each rotor, and means for rotating the rotors in opposite directions; the combination of a control lever for varying the pitches of all of the rotors of both units simultaneously and in the same sense, steering mechanism connected to said pitch varying means for varying the pitches of the clockwise rotating rotors simultaneously in one sense and varying the pitches of the counterclockwise rotating rotors simultaneously in the opposite sense and a stabilizing lever movable in one plane for varying the pitches of the rotors of one of said units in one sense and simultaneously varying the pitches of the rotors of another unit in the opposite sense, said stabilizing lever being movable in a plane at a right angle to the first mentioned plane and connected with the means for projecting and retracting the propeller blades of both units to vary the extent of projection of said-blades.

11. In a helicopter, the combination of a pair of rotor units, each unit comprising a pair of coaxial, variable pitch rotors having at leasttwo wings, shiftable cam means for varying the sectional shape of said Wings cyclically, axially shift- :able means for varying th'e'pitches of said rotors, a rotatable and axially movable shaft connecting said axially shiftable means, for varying the pitches of said rotors in the same sense upon axial movement, and in opposite senses upon rotary movement, and means for rotating said rotors in opposite directions; the combination of a control lever connected to said shafts of both of said units for shifting said shafts axially simultaneously to vary the pitches of all of said rotors in the same sense, a universally mounted lever connected to said shafts and. to said cam means of both of said rotors for shifting said'shafts axially to vary the pitches of the rotors of one unit in one sense and the pitches of the rotors of the other unit in the opposite sense upon movement of the iever in, one plane, and for shifting the cam means of both units in the same directions upon movement in a plane at a right angle to the first mentioned planes, and steering mechanism connected to said shafts for rotating the shafts of said units, simultaneously.

:12. In a helicopter, the combination of an elongated body, a counter-rotating, coaxial rotor unit adjacent each end of said body, each unit having an engine, a pair of variable pitch rotors, means for "controlling the pitch of individual rotors, and a transmission driven by said engine for rotating said rotors in opposite directions, means connecting said rotor units to enable each engine to drive all of said rotors at a constant speed-relationship regardless of variation in the individual pitch setting of the rotors, and means 16 including control connections interconnecting the pitch control means of both of said rotor units for varying the pitches of the rotors of both units simultaneously in the same sense, to control ascent and descent of the helicopter without relative fore-and-ait pitching movement.

13. In a helicopter, the combination of an elongated body, a counter-rotating, coaxial rotor unit adjacent each end of said body, each unit having an engine, a pair of variable pitch rotors, means for controlling the pitch of individual rotors, and a transmission driven by said engine for rotating said rotors in opposite directions, means connecting said rotor units to enable each engine to drive all of said rotors at a constant speed-relationship, and means including control connections interconnecting the pitch control means of both of said rot-or units for varyingthe pitches of the rotors of said units simultaneously in opposite senses to control fore-and-aft pitching movement of the helicopter.

3.4. In a helicopter, the combination of an elongated body, a counter-rotating, coaxial rotor unit adjacent each end of said body, each unit having an engine, a pair of variable pitch rotors, means for controlling the pitch of individual rotors, and a transmission driven by said engine for rotating said rotors in opposite directions, means connecting said rotor units to enable each engine to drive all of said rotors at a constant speed-relationship, and'means including control connections interconnecting the pitch control means of both of said rotor units for varying the pitches of oppositely rotating rotors in opposite senses to effect the steering of the helicopter.

15. In a helicopter, the combination of an elonated body, counter-rotating variable pitch rotor units at opposite ends of said body, means for controlling the pitch of individual rotors, each unit having an engine and a transmission driven by said engine for rotating said rotors in opposite directions, means connecting said rotor units to enable each engine to drive both of said rotor units at a constant speed'relationship regardless of variation in the individual pitch setting of the rotors, and means including control connections interconnecting the pitch control means of both of said rotor units for varying thepitches of the rotors of both units simultaneously in the same sense and including control connections for varying the pitch of one unit in one sense and the pitch of the other unit in the opposite sense.

16. In a helicopter, the combination of an elongated body, counter-rotating variable pitch rotor units at opposite ends of said body, each rotor having at least one Wing, means for cyclically varying the sectional shape of each wing, means for controlling the pitch of individual rotors, means for rotating said rotors in opposite directions, including means interconnecting said rotor units to drive both of said units at a constant speed-relationship, and control means including control connections interconnecting the pitch control means of both of said rotor units for selectively varying the pitches of said rotors to regulate their lift and their torque reactions, and including control connections interconnecting said sectional shape varying means of both of said units.

VINCENT BENDIX. 

